Added links to all scanners supported by hp3900 (bug #302968).

unsupported/hp-scanjet-3970c.html

@@ -40,9 +40,9 @@ TAIWAN
     </p>
     <h2>Comments</h2>
     <p>
-      A <a href="http://sourceforge.net/projects/hp3900-series/">project to
+      Actually there is now an <a
-	develop a backend</a> for this scanner has been started by Jonathan
+      href="http://sourceforge.net/projects/hp3900-series/">external backend</a> for this
-      Bravo Lopez (2005-10-19).
+      scanner made by Jonathan Bravo Lopez.
     </p>
     <p>
       Maybe similar to <a href="hp-scanjet-3570c.html">HP ScanJet

unsupported/hp-scanjet-4070.html

@@ -34,6 +34,11 @@
       RTS8822L  Realtek
     </p>
     <h2>Comments</h2>
+    <p>
+      Actually there is now an <a
+      href="http://sourceforge.net/projects/hp3900-series/">external backend</a> for this
+      scanner made by Jonathan Bravo Lopez.
+    </p>
     <p>
       Similar to HP Scanjet 3970c.
     </p>

unsupported/hp-scanjet-4370.html

@@ -35,6 +35,9 @@
     </p>
     <h2>Comments</h2>
     <p>
+      There is an <a
+      href="http://sourceforge.net/projects/hp3900-series/">external backend</a>
+      taht may work with this scanner made by Jonathan Bravo Lopez.
     </p>
     <h2>Output of /proc/bus/usb/devices or sane-find-scanner -v -v or lsusb -vv</h2>
     <pre>